What is io_uring?
An attempt at concise explanation of what io_uring is.
io_uring is a new Linux kernel interface for making
system calls. Traditionally, syscalls are submitted to the kernel
individually and
synchronously: a syscall CPU instruction transfers
control from the application to the kernel; control returns to the
application only when the syscall is completed. In contrast, io_uring is a batched and asynchronous
interface. The application submits several syscalls by writing their
codes & arguments to a lock-free shared-memory ring buffer. The
kernel reads the syscalls from this shared memory and executes them at
its own pace. To communicate results back to the application, the
kernel writes the results to a second lock-free shared-memory ring
buffer, where they become available to the application asynchronously.
You might want to use io_uring if:
- you need extra performance unlocked by amortizing userspace/kernelspace context switching across entire batches of syscalls,
- you want a unified asynchronous interface to the entire system.
You might want to avoid io_uring if:
- you need to write portable software,
- you want to use only old, proven features,
- and in particular you want to use features with a good security track record.